Of course, the most discussed topic in the design of domestic light cruisers of projects 26 and 26-bis is their armament and, first of all, the main caliber. Not only did it give rise to numerous disputes about the classification of cruisers (light or heavy?), But also the guns themselves were either considered a masterpiece of artillery work that has no analogues in the world, or were declared a deafening failure of Soviet gunsmiths, from which, when fired at close range you can't even get into the Crimean peninsula.
So, I. F. Tsvetkov in his work "Guards cruiser" Krasny Kavkaz "tells about the prototype of the guns of the cruisers of the" Kirov "class in the most superlative degree:
The design bureau of the Bolshevik plant (formerly the Obukhov plant of the Maritime Department) has developed a 180-mm gun with a barrel length of 60 calibers. It was the first weapon of a new generation of naval artillery after the revolution. It possessed unique ballistic characteristics and was far superior to foreign counterparts. Suffice it to say that with a projectile mass of 97.5 kg and an initial speed of 920 m / s, the maximum firing range of the gun reached more than 40 km (225 cables)."
But A. B. Shirokorad in his work "The Battle for the Black Sea" speaks of 180-mm cannons much more derogatory:
“A group of gunners proposed to create an ultra-long-range 180-mm naval gun. The 180-mm cannon fired at a distance of up to 38 km with projectiles weighing 97 kg, and the armor-piercing projectile contained about 2 kg of explosive, and the high-explosive one - about 7 kg. It is clear that such a projectile could not inflict serious damage to an enemy cruiser, not to mention battleships. And worst of all, it was possible to get into a moving battleship, and even more so into a cruiser from a distance of over 150 cables (27.5 km), only by accident. By the way, the "General Firing Tables" (GTS) for 180-mm guns were calculated only up to a distance of 189 cables (34, 6 km), while the mean deviation in range was over 180 m, i.e. no less cable. Thus, from the firing tables it follows that the red military men from 180-mm guns were not going to shoot even at coastal targets. The probability of dispersion in the range was over 220 m, and lateral - over 32 m, and then theoretically. And then practically we didn’t have fire control devices (PUS) to shoot at such distances”.
Thus, some authors admire the power and record range of the Soviet gun, while others (critics, which are the majority) point to the following shortcomings:
1. Rapid barrel wear and, as a consequence, low survivability of the latter.
2. Low shooting accuracy.
3. Low rate of fire, due to which the 180-mm cannon is inferior even to 152-mm artillery systems in terms of fire performance.
4. Low survivability of the three-gun mount due to the placement of all three guns in one cradle.
In recent years, it has been widely believed that the aforementioned shortcomings made our 180mm cannons almost unusable. Without pretending to be the ultimate truth, let's try to figure out how justified these claims to the main caliber of our cruisers are.
The main weapon of each cruiser of the project 26 or 26-bis consisted of nine 180-mm / 57 B-1-P cannons, and to begin with, we will tell the story of the appearance of this artillery system as most sources give it today.
The B-1-P was a "descendant", or rather, a modernization of the 180-mm / 60 B-1-K cannon, developed in 1931. Then the domestic design idea swung at a lot. First, it was decided to obtain record ballistics in order to fire a 100 kg projectile with an initial speed of 1000 m / s. Secondly, it was planned to achieve a very high rate of fire - 6 rds / min, which required loading at any elevation angle.
Large-caliber guns of those times did not have such a luxury, charging at a fixed angle, i.e. after the shot, it was necessary to lower the gun to the loading angle, load it, again give it the desired sight and only then shoot, and all this, of course, took a lot of time. Loading at any elevation angle made it possible to shorten the reloading cycle and increase the rate of fire, but for this, the designers had to perch the rammer on the swinging part of the gun and provide for a very cumbersome design for the ammunition supply. In addition, it was decided to switch from cartridge-type loading to separate-case loading, as was customary for large guns of the German fleet, which made it possible to use a wedge bolt, which also reduces the reloading time. But at the same time, when designing the B-1-K, there were also very archaic solutions - the barrel was made fastened, i.e. did not have a liner, which is why after his execution it was necessary to change the body of the gun. In addition, the barrel was not purged, due to which the powder gases got inside the tower, the rangefinder was not installed, and there were other disadvantages.
The first experience in the development of a domestic naval medium-caliber artillery system turned out to be negative, since the parameters set during the design were not achieved. So, to ensure the required ballistics, the pressure in the barrel bore had to be 4,000 kg / sq. cm, but steel capable of withstanding such pressure could not be created. As a result, the pressure in the barrel had to be reduced to 3,200 kg / sq. cm, which provided a 97, 5-kg projectile with an initial speed of 920 m / s. However, even with such a decrease, the barrel survivability turned out to be extremely low - about 50-60 shots. With great difficulty, the practical rate of fire was brought to 4 rds / min. but in general neither the B-1-K nor the single-gun turret, in which this artillery system was installed on the cruiser Krasny Kavkaz, was considered successful.
The fleet needed a more advanced gun and it was made on the basis of the B-1-K, but now its design was treated more conservatively, abandoning most of the innovations that had not justified themselves. The gun was loaded at a fixed angle of 6, 5 degrees, from the wedge gate and separate-sleeve loading they returned to the caps and the piston gate. Since the power of the gun in comparison with the original requirements had to be reduced from the planned 1000 m / s for a 100 kg projectile to 920 m / s for a 97.5 kg projectile, the barrel length was reduced from 60 to 57 calibers. The resulting gun was called B-1-P (the last letter meant the type of shutter "K" - wedge, "P" - piston), and at first the new artillery system did not have any other differences from the B-1-K: for example, its barrel also performed fastened.
But soon the B-1-P underwent a series of upgrades. First, the USSR purchased equipment from Italy for the production of liners for naval artillery, and in 1934 the first 180-mm lined gun was already tested at the test site, and later the fleet ordered only such guns. But even with lined B-1Ps, the barrel survivability increased very slightly, reaching 60-70 shots, against 50-60 B-1-K shots. This was unacceptable, and then the survivability of the barrels was corrected by increasing the depth of the rifling. Now the deep-groove liner withstood not 60-70, but as many as 320 shots.
It would seem that an acceptable indicator of survivability has been achieved, but that was not the case: it turns out that Soviet sources do not mention one very interesting detail: such survivability was ensured not by the depth of the rifling, but … by changing the criteria for barrel wear. For B-1-K and B-1-K with fine rifling, the barrel was considered shot if the projectile lost 4% of its initial speed, but for lined barrels with deep grooves, this figure was increased to 10%! It turns out that, in fact, nothing has changed much, and the required indicator was simply "stretched" by increasing the wear criterion. And taking into account Shirokorad's categorical statements about the extremely low accuracy of our guns at long distances ("getting into a moving battleship or cruiser … can only be completely by accident"), readers interested in the history of the Russian fleet had a completely unsightly picture in which, what is most sad, very easy to believe.
It turned out that the developers of the B-1-K and B-1-P, in pursuit of records, overloaded the cannon with an excessively powerful charge and a heavy projectile, the artillery system simply could not withstand the maximum loads for it for some time (such weapons are called over-powered) … From this, the barrel was subjected to extremely rapid burnout, as a result of which the accuracy and accuracy of fire was quickly lost. At the same time, the gun did not differ in accuracy even in the "non-fired" state, but taking into account the fact that the accuracy dropped after a few dozen shots … And if you also remember that three barrels in one cradle were too close to each other, which the shells leaving on their last flight affected the powder gases from neighboring barrels, knocking them down the correct trajectory, it turns out … That the pursuit of "faster, higher, stronger", so characteristic of the 30s of the last century, once again resulted in sheer eyewash and a scam. And the sailors received completely unusable weapons.
Well, let's go from afar. Here is A. B. Shirokorad writes: "The mean deviation in range was over 180 m." What is this median deviation in general and where does it come from? Let's remember the basics of artillery. If you aim the cannon at a certain point on the surface of the earth and, without changing the sight, make some shots, then the shells fired from it will not fall one after the other at the aiming point (like Robin Hood's arrows split one another in the center of the target), but will fall at some distance from it. This is due to the fact that each shot is strictly individual: the mass of the projectile differs by fractions of a percent, the quantity, quality and temperature of the powder in the charge differ slightly, the sight is lost by thousandths of a degree, and gusts of wind affect the flying projectile even a little, but all -so differently than on the previous one - and as a result, the projectile will fall a little further or a little closer, a little to the left or a little to the right of the aiming point.
The area into which the projectiles fall is called the dispersal ellipse. The center of the ellipse is the aiming point where the gun was aimed. And this scattering ellipse has its own laws.
If we divide the ellipse into eight parts along the direction of flight of the projectile, then 50% of all projectiles fired will fall into the two parts that are directly adjacent to the aiming point. This law works for any artillery system. Of course, if you fire 20 shells from the cannon without changing the sight, then it may well happen that 10, and 9 or 12 shells will hit the two indicated parts of the ellipse, but the more shells are fired, the closer to 50% the final result will be. One of these parts is called the median deviation. That is, if the median deviation at a distance of 18 kilometers for a gun is 100 meters, then this means that if you absolutely accurately aim the gun at a target located 18 km from the gun, then 50% of the projectiles fired will fall on a segment of 200 meters, the center which will be the aiming point.
The larger the median deviation, the larger the scattering ellipse, the smaller the median deviation, the greater the chances of the projectile hitting the target. But what does its size depend on? Of course, it depends on the accuracy of the gun firing, which, in turn, is influenced by the quality of the gun and shells. Also - from the distance of fire: if you do not delve into some nuances that are unnecessary for a layman, then the greater the distance of fire, the lower the accuracy and the greater the median deviation. Accordingly, the median deviation is a very good indicator characterizing the accuracy of the artillery system. And in order to understand what the B-1-P was in terms of accuracy, it would be nice to compare its mean deviations with the guns of foreign powers … but it turned out to be quite difficult.
The fact is that such data cannot be found in ordinary reference books; this is very specialized information. So, for Soviet artillery systems, the median deviations of a particular gun are contained in a special document "Basic firing tables", which was used by artillerymen to control fire. Some "Tables" can be found on the Internet, and the author of this article was able to get hold of "Tables" of domestic 180-mm guns.
But with foreign naval guns, the situation is much worse - perhaps there is such data somewhere in the network, but, alas, it was not possible to find them. So what is the B-1-P to be compared to?
In the history of the Russian fleet, there were artillery systems that never caused any complaints from naval historians. Such, for example, was the 203 mm / 50 gun, on the basis of which, in fact, the B-1-K was designed. Or the famous Obukhovskaya 305-mm / 52, which was used to arm the battleships of the Sevastopol and Empress Maria types - it is universally considered an exemplary killing machine. No one has ever reproached these artillery systems for excessive dispersion of shells, and data on their median deviations are in Goncharov's "Course of Naval Tactics" (1932).
Note: firing distances are indicated in cables and are converted to meters for ease of perception. The average deviations in the documents are indicated in fathoms, and also, for convenience, converted to meters (1 fathom = 6 feet, 1 foot = 30.4 cm)
Thus, we see that the domestic B-1-P is much more accurate than the "tsarist" guns. In fact, our 180-mm artillery system hits 90 kbt more accurately than 305-mm dreadnought cannons - 70 kbt, and with 203-mm / 50 there is no comparison at all! Of course, progress does not stand still, and perhaps (since the author could not find data on the median dispersion of imported guns) the artillery of other countries fired even more accurately, but if the accuracy of 305-mm guns (with much worse fire control systems) was considered sufficient for defeat of surface targets, then why would we consider a much more accurate 180-mm gun "clumsy"?
And those fragmentary data on the accuracy of foreign guns, which are still on the network, do not confirm the hypothesis about the poor accuracy of the B-1-P. For example, there is data on the German 105-mm field gun - its median deviation at a distance of 16 km is 73 m (for the B-1-P at this distance - 53 m), and at the 19 km limit for it, a German woman has 108 m (B -1-P - 64 m). Of course, it is impossible to compare the land "weaving" with a naval cannon of almost twice the caliber "head-on", but nevertheless, these figures can give some idea.
The attentive reader will pay attention to the fact that the "Basic shooting tables" I cite were compiled in 1948, i.e. after the war. What if by that time the USSR had learned to make some better quality liners than the pre-war ones? But in fact, the firing tables for the intensive combat were compiled on the basis of the actual firing in September 1940:
In addition, this screenshot clearly confirms that the tables used not calculated, but actual values based on the results of the shooting.
But what about the low survivability of our guns? After all, our guns are overpowered, their barrels burn out in a few dozen shots, the accuracy of fire drops rapidly, and then the mean deviations will exceed their tabular values … Stop. And why did we decide that our 180-mm cannons had low survivability?
“But how ?! - the reader will exclaim. “After all, our designers, in pursuit of record performance, managed to bring the pressure in the barrel bore up to 3,200 kg / sq.see why the trunks burned out quickly!"
But here's what is interesting: the German gun 203-mm / 60 model SkL / 60 Mod. C 34, which was armed with cruisers of the "Admiral Hipper" type, had exactly the same pressure - 3,200 kg / sq. see It was that monster, firing 122 kg shells with an initial speed of 925 m / s. Nevertheless, no one ever called it overrated or inaccurate, on the contrary - the gun was considered a very outstanding representative of medium-caliber naval artillery. At the same time, this gun convincingly demonstrated its qualities in the battle in the Danish Strait. The heavy cruiser "Prince Eugen", firing at a distance of 70 to 100 kbt in 24 minutes, achieved at least one hit on the "Hood" and four hits on the "Prince of Wells". In this case, the survivability of the barrel (according to various sources) ranged from 500 to 510 shots.
We can, of course, say that the German industry was better than the Soviet one and made it possible to produce better weapons. But not by an order of magnitude! Interestingly, according to some sources (Yurens V. “The death of the battle cruiser“Hood”), the median deviation of the German 203-mm cannon approximately corresponds (and even slightly higher) to that of the Soviet 180-mm artillery system.
Rifling depth? Yes, in B-1-K the grooves are 1.35 mm, and in B-1-P - as much as 3.6 mm, and such growth seems to look suspicious. But here's the thing: the German 203-mm / 60 had a groove depth of 2.4 mm, i.e. significantly more than that of the B-1-K, although almost one and a half times less than that of the B-1-P. Those. the increase in the depth of the rifling is to a certain extent justified, since for their performance characteristics in the B-1-K they were simply underestimated (although, perhaps, they were somewhat overestimated in the B-1-P). You can also recall that the 152-mm gun B-38 (the accuracy of which, again, no one ever complained about) had a rifling depth of 3.05 mm
But what about the increase in the criteria for shooting a gun? After all, there is an absolutely exact fact: for the B-1-K, 100% barrel wear was considered when the projectile speed dropped by 4%, and for the B-1-P, the speed drop was as much as 10%! Means, all the same eyewash?
Let me offer you, dear readers, a hypothesis that does not claim to be an absolute truth (the author of the article is still not an artillery specialist), but explains well the increase in the wear criteria for B-1-P.
First. The author of this article tried to find out what criteria for the shooting of guns were used abroad - this would make it possible to understand what was wrong with the B-1-P. However, such information could not be found. And here is L. Goncharov in his work “Course of naval tactics. Artillery and Armor "1932, which, generally speaking, served as a training manual for artillery, indicates the only criterion for the survivability of the gun -" the loss of stability by the projectile. " In other words, the gun cannot be shot so much that its projectile begins to tumble in flight, because in this case, if it hits, it can either collapse before an explosion, or the fuse will not work. It is also clear that the breakdown of armor from an armor-piercing projectile should be expected only if it hits the target with its "head" part, and does not flop on it flat.
Second. By itself, the wear criterion of the barrel of Soviet guns looks utterly surprising. Well, the speed of the projectile dropped by 10%, so what? Is it difficult to foresee an appropriate amendment when shooting? Yes, not at all - the same "General Firing Tables" give a whole set of corrections for each percentage drop in the speed of shells, from one to ten. Accordingly, it is possible to determine the amendments for both 12- and 15-percent falls, it would be desirable. But if we assume that the change in the speed of the projectile itself is uncritical, but with a corresponding drop in speed (4% for B-1-K and 10% for B-1-P), something happens that prevents normal firing from the gun - then everything becomes clear.
Third. B-1-P has increased rifling depth. What for? What is a cannon rifling for? The answer is simple - a projectile "twisted" by grooves has greater stability in flight, better range and accuracy.
Fourth. What happens when a shot is fired? The projectile is made of very strong steel, on top of which a so-called "belt" of mild steel is installed. Mild steel "squeezes" into the grooves and spins the projectile. Thus, the barrel "in the depth" of the groove interacts with the soft steel of the "shell belt", but "over" the groove - with the very hard steel of the shell itself.
Fifth. Based on the foregoing, we can assume that rifling depth decreases when firing a cannon. Simply because the “top” wears off on the hard steel of the projectile faster than the “bottom” on the soft one.
And if our assumption is correct, then the “chest” opens very easily with increasing groove depth. Shallow grooves B-1-K were erased very quickly, and already when the speed dropped by 4%, the projectile ceased to "twist" sufficiently by them, and this is expressed in the fact that the projectile ceased to "behave" in flight as expected. Perhaps he lost stability, or the accuracy dropped sharply. A gun with deeper grooves retains the ability to adequately "twist" the projectile even when its initial velocity drops by 4%, and by 5%, and by 8%, and so on up to 10%. Thus, there was no decrease in the survivability criteria for the B-1-P in comparison with the B-1-P.
Of course, all of the above, although it very well explains both the reason for the increase in rifling depth and the decrease in survivability criteria for the B-1-P gun, is still nothing more than a hypothesis, and expressed by a person who is very far from artillery work.
An interesting nuance. Reading sources about Soviet cruisers, one can come to the conclusion that a shot (that is, a projectile and a charge) at which 97.5 kg of a projectile was given an initial velocity of 920 m / s is the main one for our 180-mm cannons. But this is not the case. The initial speed of 920 m / s was provided with an intensified combat charge, weighing 37.5 kg, but besides it there was a combat charge (weight -30 kg, accelerated 97.5 kg projectile to a speed of 800 m / s), a reduced combat charge (28 kg, 720 m / s) and reduced (18 kg, 600 m / s). Of course, with a decrease in the initial speed, the survivability of the barrel increased, but the armor penetration and firing range fell. The latter, however, is not so essential - if the intensive combat provided a maximum firing range of 203 kbt, then being the main combat charge, it "threw" a projectile of a 180-mm cannon at 156 kbt, which was more than enough for any naval battle.
It should be noted that some sources indicate that the barrel survivability of the 180-mm B-1-P cannon in 320 rounds is ensured when using a combat charge, and not an enhanced combat charge. But, apparently, this is a mistake. According to the 1940 "Instructions for determining the wear of channels 180/57 of naval artillery guns" quoted on the Internet (RGAVMF Fond R-891, No. 1294, op.5 d.2150), "the replacement of the gun was subject after 90% wear - 100% wear was 320 intense combat shots V = 920 m / s or 640 for a war charge (800 m / s) ". Unfortunately, the author of the article does not have the opportunity to check the accuracy of the citation, since he does not have a copy of the "Instruction" (or the opportunity to visit the RGA of the Navy). But I would like to note that such data correlate much better with the survivability of the German 203-mm cannon than the idea that with equal pressure inside the barrel (3,200 kg / sq. Cm), the Soviet 180-mm had a survivability of only 70 shots against 500 -510 for the German.
In general, it can be stated that the firing accuracy of the Soviet B-1-P cannon is quite sufficient for confidently hitting sea targets at any reasonable range of artillery combat, and, although questions about its survivability remain, most likely the publications of recent years have greatly thickened the colors on this question.
Let's move on to the towers. Cruisers of the type "Kirov" and "Maxim Gorky" carried three three-gun turret mounts MK-3-180. The latter are traditionally blamed for the "one-shell" design - all three B-1-P guns were located in a single cradle (like the Italian cruisers, the only difference is that the Italians used two-gun turrets). There are two complaints about this arrangement:
1. Low survivability of the installation. When the cradle is disabled, all three guns become unusable, while for an installation with individual guidance of each gun, damage to one of the cradles would disable only one gun.
2. Due to the small distance between the barrels during salvo firing, gases from neighboring barrels act on the shell that has just left its barrel and "knock down" its trajectory, which greatly increases the dispersion and loses the shooting accuracy.
Let's figure out what we lost and what our designers gained using the "Italian" scheme.
I would like to say right away that the claim about the survivability of the installation is somewhat far-fetched. Purely theoretically, of course, it is possible that one or two turret guns fail, and the rest continue to shoot, but in practice this almost never happened. Almost the only such case is damage to the turret of the battle cruiser "Lion", when the left gun was out of order, and the right one continued to shoot. In other cases (when one turret gun fired and the other did not), the damage usually has nothing to do with the vertical aiming device (a piece of the barrel is knocked off by a direct hit, for example). Having received similar damage to one gun, other MK-3-180 guns could well continue the battle.
The second claim is much more weighty. Indeed, having a distance between the axes of the guns of only 82 cm, the MK-3-180 could not carry out salvo firing in any way without some loss in accuracy. But here there are two important nuances.
Firstly, the fact is that firing with full volleys before the First World War was practically not practiced by anyone. This was due to the peculiarities of conducting firefighting - to ensure effective zeroing, at least four guns in a salvo were required. But if more of them fired, then it did little to help the artillery officer of the shooting ship. Accordingly, a ship with 8-9 main-caliber cannons usually fought in half-salvoes, each of which involved 4-5 guns. That is why, in the opinion of the naval gunners, the most optimal layout for the main guns was four two-gun turrets - two in the bow and two in the stern. In this case, the ship could shoot at the bow and stern with full volleys of the bow (stern) towers, and when firing on board - with half-volleys, and each of the four towers fired from one gun (the second was being reloaded at this time). A similar situation was in the Soviet fleet, so "Kirov" could easily fire, alternating four- and five-gun salvoes
Note: Shooting barrels are highlighted in red
At the same time, the distance between the barrels of firing guns increased significantly and amounted to 162 cm. This, of course, did not reach 190 cm for the 203-mm towers of Japanese heavy cruisers, and even more so - up to 216 cm towers of the Admiral Hipper-class cruisers, but still was not an extremely small value.
In addition, it should be borne in mind that it is still not very clear how much the accuracy of fire is reduced during salvo firing with the "one-arm" placement of the guns. Usually, on this occasion, the monstrous dispersal of the guns of the Italian fleet is remembered, but according to many researchers, it is not so much the placement of all the barrels in one cradle that is to blame for them, but the ugly quality of the Italian shells and charges, which differed greatly in weight. In the event that high-quality shells were used (shells made in Germany were tested), then the dispersion turned out to be quite acceptable.
But not only Italian and Soviet turret mounts placed all the guns in one cradle. The Americans also sinned the same - the turret guns of the first four series of heavy cruisers (Pensacola, Northampton, Portland, New Orleans) and even some battleships (Nevada and Pennsylvania types) were also deployed in one carrycot. Nevertheless, the Americans got out of this situation by placing time-delay machines in the towers - now the guns were fired into a salvo with a delay of hundredths of a second, which significantly increased the accuracy of fire."On the Internet" the author came across allegations that such devices were installed on the MK-3-180, but documentary evidence of this could not be found.
But still, according to the author, "one-arm" tower installations have another significant drawback. The fact is that in the Soviet fleet (and not only in it, the method described below was known even during the First World War) there was such a concept as "ledge shooting". Without going into unnecessary details, we note that earlier, when zeroing in with a "fork", each next volley (half-salvo) was made after observing the fall of the previous shells and introducing the corresponding adjustment of the sight, i.e. a lot of time passed between the volleys. But when zeroing in with a "ledge" half of the guns were given one sight, the second half - slightly modified, with an increased (or reduced) range. Then two half-shots were made with a difference of several seconds. As a result, the artillery officer could assess the position of the enemy ship in relation to the falls of two half-salvoes, and it turned out that it was much more convenient and faster to determine the amendments to the sight. In general, shooting with a "ledge" made it possible to shoot faster than when shooting with a fork.
But firing "ledge" from "one-arm" installations is difficult. In an ordinary turret, there is nothing complicated - I set one elevation angle for one gun, another for another, and in the MK-3-180, when aiming, all the guns received the same angle. Of course, it was possible to do a half-shot, then change the aiming and make a second one, but it was all slower and more complicated.
However, the "one-man" installations had their own advantages. The placement of guns on different cradles encountered the problem of misalignment of the axes of the guns: this is a situation when the guns in the turret have the same sight, but due to the mismatch in the position of the individual cradles, they have slightly different elevation angles and, as a result, increased spread in the salvo … And, of course, the "one-arm" tower installations greatly benefitted in terms of weight and dimensions.
For example, the rotating part of the three-gun 180-mm turret of the cruiser "Kirov" was only 147 tons (247 tons is the total weight of the installation, taking into account the mass of the barbet), while the tower was protected by 50 mm armor plates. But the rotating part of the German three-gun 152-mm turret, in which the guns were placed individually, weighed almost 137 tons, while its frontal plates were only 30 mm thick, and the sides and roof were generally 20 mm. The rotating part of the 152-mm two-gun British turret of the Linder-class cruisers had only one inch protection, but at the same time weighed 96.5 tons.
Moreover, each Soviet MK-3-180 had its own rangefinder and its own automatic fire, i.e. actually duplicated the centralized fire control, albeit in miniature. Neither the English, nor the German towers, nor rangefinders, nor (all the more so!) Had automatic firing.
It is interesting to compare the MK-3-180 with the three-gun turrets of the 152-mm guns of the Edinburgh cruiser. Those had slightly better armor (side and roof - the same 50 mm, but the frontal plate - 102 mm of armor) had neither rangefinders nor automatic firearms, but their rotating part weighed 178 tons. However, the weight advantages of the Soviet towers did not end there. Indeed, in addition to the rotating part, there are also non-rotating structural elements, of which the barbet has the largest mass - an armored "well" connecting the tower and reaching either the armored deck or the very cellars. The barbet is absolutely necessary, as it protects the feeding devices of projectiles and charges, preventing fire from entering the artillery cellar.
But the mass of the barbet is very large. So, for example, the mass of barbets from the cruiser of Project 68 ("Chapaev") was 592 tons, while the extended 100 mm armor belt weighed almost the same - 689 tons. A very important factor affecting the mass of the barbet was its diameter, and in the relatively medium-sized MK-3-180 it approximately corresponded to that of the three-gun 152-mm turrets with guns in individual cradles, but an attempt to place 180-mm in different cradles would lead to a significant increase in the diameter, and as a consequence - the mass of the barbet.
The conclusions are as follows. In general, a turret with guns in one cradle, although not fatal, still loses in terms of combat qualities of a turret with separate vertical guidance of guns. But in the case when the ship's displacement is limited, the use of "one-arm" towers allows for the same mass of weapons to provide greater firepower. In other words, of course, it would be better to put towers with guns in individual cradles on cruisers like Kirov and Maxim Gorky, but a significant increase in displacement should be expected. And in the existing scales, our cruisers could be equipped with either three three-gun turrets with 180-mm cannons in one cradle (as was done) or three two-gun turrets with 180-mm guns in different cradles, or the same number of three-gun 152-mm towers with guns in different cradles. It is obvious that, despite some shortcomings, 9 * 180 mm guns are significantly better than 6 * 180 mm or 9 * 152 mm.
On the subject of the main caliber, the problems with the rate of fire of the MK-3-180, the shells that our 180-mm cannons fired, and the fire control system should also be described. Alas, due to the large volume of material, it was not possible to fit everything into one article, and therefore …
To be continued!